I have known many RC nuns, and made retreats with them, particularly the IBVM and Carmelites. As I understand it (and I'm C of E, not Catholic) all religious are bound by Obedience, to their immediate Superior, the Superior General, their Bishop, and ultimately to Rome and The Holy Father himself. (and of course to God) Therefore I can't see how they can possibly refuse to toe the line as laid down by Rome. By flouting any rule or directive, they are in flagrant breach of the vows made at their Profession. No matter what a nun's opinion may secretly be, she is obliged to obey whatever the Vatican may choose to lay down as a Rule. Even by demonstrating in a silent insubordination, the nuns are showing disobedience. And (as I understood it from the nuns I met) even disagreeing in ones head is sinful and should be dealt with by prayer and vigilance.